I took my Mossberg out to BLM last week to do my own un-scientific test on HD Shotshells.
The top right is "Remington Ultimate Home Defense" Basically steel shot
The Bottom left is Winchester SXZ 00 Buck.
Both shot from about 15 feet out of a 20" Cylinder bore Mossberg 590
You might want to rethink that steel shot would be a tighter pattern. Also be aware that the Bird shot only penetrated 3/4 of a phone book while 00 buck tore clean through.
So both doing "the job" is in question in my opinion.

__________________A mugger, even an armed one, can only make a successful living in a society where the state has granted him a force monopoly.-Marko Kloos

"...and an old German guy said there was a bit of an unsaid joke about the Nazi salute; apparently when they clicked their heels and raised their arm up in the air in a Nazi salute, they were saying, "we're in this much s___."